package server;

import com.sun.xml.internal.ws.policy.privateutil.PolicyUtils;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.io.SAXReader;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * Minicat的主类
 */
public class Bootstrap {

    /**
     * 定义socket监听的端口号
     */
    private int port = 8080;

    public int getPort() {
        return port;
    }

    public void setPort(int port) {
        this.port = port;
    }


    /**
     * Minicat启动需要初始化展开的一些操作
     */
    public void start() throws Exception {

        // 加载解析相关的配置，web.xml
        String deployPath = loadServer();
        loadServlet(deployPath);


        // 定义一个线程池
        int corePoolSize = 10;
        int maximumPoolSize = 50;
        long keepAliveTime = 100L;
        TimeUnit unit = TimeUnit.SECONDS;
        BlockingQueue<Runnable> workQueue = new ArrayBlockingQueue<>(50);
        ThreadFactory threadFactory = Executors.defaultThreadFactory();
        RejectedExecutionHandler handler = new ThreadPoolExecutor.AbortPolicy();


        ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(
                corePoolSize,
                maximumPoolSize,
                keepAliveTime,
                unit,
                workQueue,
                threadFactory,
                handler
        );


        /*
            完成Minicat 1.0版本
            需求：浏览器请求http://localhost:8080,返回一个固定的字符串到页面"Hello Minicat!"
         */
        ServerSocket serverSocket = new ServerSocket(port);
        System.out.println("=====>>>Minicat start on port：" + port);

//        while (true) {
//            Socket socket = serverSocket.accept();
//            // 有了socket，接收到请求，获取输出流
//            OutputStream outputStream = socket.getOutputStream();
//            String data = "Hello Minicat!";
//            String responseText = HttpProtocolUtil.getHttpHeader200(data.getBytes().length) + data;
//            /*
//            byte[] bytes = responseText.getBytes();
//            System.out.println("a".getBytes()[0]);
//            for (int i = 0; i < bytes.length; i++) {
//                System.out.print(bytes[i] + " ");
//            }
//            System.out.println(bytes);
//             */
//            outputStream.write(responseText.getBytes());
//            socket.close();
//        }


        /**
         * 完成Minicat 2.0版本
         * 需求：封装Request和Response对象，返回html静态资源文件
         */
//        while (true) {
//            Socket socket = serverSocket.accept();
//            InputStream inputStream = socket.getInputStream();
//            // 封装Request对象和Response对象
//            Request request = new Request(inputStream);
//            Response response = new Response(socket.getOutputStream());
//
//            response.outputHtml(request.getUrl());
//            socket.close();
//
//        }


        /**
         * 完成Minicat 3.0版本
         * 需求：可以请求动态资源（Servlet）
         */
        while (true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();

            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());

            // 静态资源处理
            if (servletMap.get(request.getUrl()) == null) {
                response.outputHtml(request.getUrl());
            } else {
                // 动态资源servlet请求
                HttpServlet httpServlet = servletMap.get(request.getUrl());
                httpServlet.service(request, response);
            }

            socket.close();

        }


        /*
            多线程改造（不使用线程池）
         */
        /*
        while(true) {
            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket,servletMap);
            requestProcessor.start();
        }
        */

//        System.out.println("=========>>>>>>使用线程池进行多线程改造");
//        /*
//            多线程改造（使用线程池）
//         */
//        while (true) {
//
//            Socket socket = serverSocket.accept();
//            RequestProcessor requestProcessor = new RequestProcessor(socket, servletMap);
//            //requestProcessor.start();
//            threadPoolExecutor.execute(requestProcessor);
//        }


    }


    private Map<String, HttpServlet> servletMap = new HashMap<String, HttpServlet>();

    /**
     * 加载解析web.xml，初始化Servlet
     */
    private void loadServlet(String deployPath) throws IOException {
        //            InputStream fileInputStream = new FileInputStream("/Users/liujinxia/Downloads/project/lagou/Minicat/webapps/server.xml");
        InputStream resourceAsStream =new FileInputStream(deployPath+"/web.xml");
        SAXReader saxReader = new SAXReader();

        try {
            Document document = saxReader.read(resourceAsStream);
            Element rootElement = document.getRootElement();

            List<Element> selectNodes = rootElement.selectNodes("//servlet");
            for (int i = 0; i < selectNodes.size(); i++) {
                Element element = selectNodes.get(i);
                // <servlet-name>lagou</servlet-name>
                Element servletnameElement = (Element) element.selectSingleNode("servlet-name");
                String servletName = servletnameElement.getStringValue();
                // <servlet-class>server.LagouServlet</servlet-class>
                Element servletclassElement = (Element) element.selectSingleNode("servlet-class");
                String servletClass = servletclassElement.getStringValue();


                // 根据servlet-name的值找到url-pattern
                Element servletMapping = (Element) rootElement.selectSingleNode("/web-app/servlet-mapping[servlet-name='" + servletName + "']");
                // /lagou
                String urlPattern = servletMapping.selectSingleNode("url-pattern").getStringValue();
                servletMap.put(urlPattern, (HttpServlet) Class.forName(servletClass).newInstance());

            }


        } catch (DocumentException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }

    }

    /**
     * 加载解析server.xml,实现webapps部署效果
     * <Server>
     * <Service>
     * <Connector port="8080">
     * <Engine>
     * <Host name="localhost"
     * appBase="/Users/liujinxia/Downloads/project/lagou/Minicat/webapps/demo1"></Host>
     */
    private String loadServer() {
        try {
            InputStream fileInputStream = new FileInputStream("/Users/liujinxia/Downloads/project/lagou/Minicat/webapps/server.xml");
            SAXReader saxReader = new SAXReader();

            Document document = saxReader.read(fileInputStream);
            Element rootElement = document.getRootElement();
            Element hostElement = (Element) rootElement.selectSingleNode("//Server/Service/Connector/Engine/Host");
            String appBase = hostElement.attributeValue("appBase");
            System.out.println("-------");
            System.out.println(appBase);
            return appBase;
        } catch (IOException e) {
            e.printStackTrace();
        } catch (DocumentException e) {
            e.printStackTrace();
        }
        return null;
    }


    /**
     * Minicat 的程序启动入口
     *
     * @param args
     */
    public static void main(String[] args) {
        Bootstrap bootstrap = new Bootstrap();
        try {
            // 启动Minicat
            bootstrap.start();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
